Transmit modules, also known more generally as front-end modules, in wireless communication systems such as GSM/CDMA or mixed-mode handsets or WLAN transceivers, support various frequency bands and/or various modulation schemes. This results in multiple ports, referred to herein as radio frequency (RF) ports, through which signals pass to integrated circuits in the RF portion of the wireless communication system.
The continuing miniaturization of electronic components in wireless communication systems can result in RF ports that are located in close proximity to one another. RF ports located in close proximity to one another can result in poor signal isolation, which can result in, for example, cross talk and electrical noise that affect signal integrity.